Chapter 7-8 Flashcards
Sensation
The process in which our sense organs and receptors detect and respond to sensory information that stimulates them
Perception
Refers to the process by which we give meaning to sensory information
Perception process: reception
The process of detecting and responding to incoming sensory information. Occurs in the receptive field
Perception process: transduction
The process by which the receptors change the energy of the detected sensory information into action potentials.
Perception process: transmission
The process of sending action potentials to relevant areas of the brain. Occurs in the primary gustatory cortex or the primary olfactory cortex.
Perception process: interpretation
The process in which incoming sensory information is given meaning so that it can be understood.
Characteristics of rods
Mainly in the periphery
Distributed in the outer reaches of the retina
More sensitive to light, operates best in dim light
Provides no colour information
Signals rough outlines of objects in peripheral vision
120 million per eye
Characteristics of cones
Mainly in the fovea Less sensitive to light, operates better in bright light Enables clear central vision Enables coloured vision 6 million per eye
Define cornea
It is a convex shaped covering that protects the eye and helps it to focus light rays on the retina
Define aqueous humour
It is a fluid that maintains the shape of the eye and carries waste out
Define pupil
The pupil is controlled by the iris to determine how much light enters the eye
Define iris
A rung of muscle that contracts and expands to let light in
Define lens
A flexible structure that helps focus light onto the the retina by adjusting its shape
Define ciliary muscles
Expand and contract allowing the lens to focus nearby objects onto the retina or focus on objects far away
Define vitreous humour
A jelly like substance that helps maintain the shape of the eyeball
Define retina
receives light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition.
Define ganglion cells
They generate action potential that enables transmission of info to the brain
Define optic nerve
Made of ganglion cells and transmits the information from the eye to the primary visual cortex
Pathway from receptive field to appropriate cortex: eye
Light enters through the CORNEA
and passes through the AQUEOUS HUMOUR.
the passage of light continues through the PUPIL and IRIS.
it enters the LENS
and continues into the VITREOUS HUMOUR.
the RETINA absorbs the light and processes the image.
The OPTIC NERVE then transmits the information to the primary visual cortex
Define Visual fields
Info from the RIGHT VISUAL FIELD enters the LEFT SIDE OF EACH EYE and is transmitted to the LEFT PRIMARY CORTEX.
Info from the LEFT VISUAL FIELD enters the RIGHT SIDE OF EACH EYE and is transmitted to the RIGHT PRIMARY CORTEX
Define gestalt principles
Refers to the ways we organise the features of a visual scene by grouping them to perceive a whole complete form
What are the gestalt principles?
Figure ground, closure, similarity, proximity
Define figure ground
When we divide a scene into two by making one the centre of focus and the other info the background. Contour is what separates the two.
Define closure
The tendency to mentally fill in gaps in an image to perceive the objects as a whole.
Define similarity
The tendency to perceive parts of an image that have similar features as belonging together as a whole
Define proximity
The tendency to perceive parts of an image which are positioned close together as belonging to a group.
Define depth cues
Sources of information from the environment (external cues) or within our body (internal cues) that help us perceive how far away an object is
Define binocular depth cues
Requires both eyes to provide information to the brain about depth and distance, convergence and retinal disparity
Monocular depth cues
Require the use of only one eye to provide the brain information about depth cues and distance
What are the binocular depth cues?
Convergence, retinal disparity
What are the monocular depth cues?
Accomodation, linear perspective, interposition, texture gradient, relative size, height in the visual field
Define convergence
Involves the brain detecting and interpreting depth or distance from changes in the eye when it moves inwards to focus on close objects or outwards to focus on objects further away
Define retinal disparity
Refers to the slight differences in the location of visual images on the retina which allows us to judge the depth or distance of an object.
Define Accomodation
The adjustment of the shape of the lens to focus an object in response to changes in how far away the object is.
Define linear perspective
The convergence of parallel lines as they recede into the distance
Define interposition
Occurs when one object partially blocks or covers another.
Define texture gradient
The gradual reduction in five detail that occurs in a surface as it recedes into distance
Define relative size
The tendency to visually perceive objects that produce the largest image in the retina as closer and the object that’s projects a smaller image as further away
Define height in visual field
In which the location of objects in our visual field are perceived as further away if it’s closer to the horizon and closer if it’s further from the horizon.
Define Perceptual consistencies
The tendency to perceive an object as unchanging despite any changes that may occur to the image cast onto the retina
What are the perceptual consistencies?
Size, shape and brightness
Define size
Involves recognising that an object’s size remains the same even though the size of the image cast onto the retina is changing
Define shape
The tendency to perceive an object as maintaining its shape despite any change in the shape of the image cast onto the retina
Define brightness
The tendency to perceive an object as maintaining its level of brightness in relation to its surroundings despite changes in the amount of light being reflected from the object to the retina
Define perceptual set
The readiness to perceive something in accordance with what we expect it to be
What are the influences in perceptual set?
Context, motivation, emotional state, past experience culture.
Define context
Refers to the setting or environment in which a perception is made
Define motivation
Refers to the process which activates behaviour that we direct to achieving a goal. We see what we want to see.
Define emotional state
How we are feeling and different emotions can influence how we see something.
Define past experience
Refers to experiences throughout life, everything we learn intentionally and unintentionally.
Define culture
Refers to the way of life of a particular group or community. Cultures include customs, traditions, beliefs etc
What are the 5 basic tastes?
Sweet, sour, salty, bitter and umami
Define sweet
Caused by sugar and it’s derivatives such as fructose and artificial sweeteners
Define sour
The more acidic the food, the more sour it will be. Tasting sour helps us judge whether a food is safe to eat or not
Define salty
Table salts and mineral salts cause a sensation of saltiness. Almost every fluid in our body contains it.
Define bitter
Produced by a variety of different substances. Finding bitter undesirable helps us steer away from poisonous foods.
Define umami
A rich taste in protein based foods due to the presence of glutamate. Also known as savoury
What are the Influences on taste perception
Age, genetics, perceptual set and cultural
Age:
We are born with the ability to taste many substances.
We lose taste buds during childhood until the final total is reached
Taste perception fades with age however it is a problem with smell.
Genetics:
Genetic differences makes us more or less sensitive to the chemical molecules in differentw foods.
Perceptual set
Our expectation of how food should look can override what we taste
Packaging or arrangement of food influences our perception of taste as taste perception begins with the eye.
Cultural:
The foods we’re exposed to from birth is reflected in our judge of tastes good and bad.
Direct experience with foods has a large effect on our taste perception as most of this experience occurs within a family setting.
What is perceptual distortion?
A mismatch between perceptual experience and physical reality .
Describe the muller-layer illusion
A visual illusion in which two lines are equal length however seen as different due to the fact that one has an arrowhead and the other a fishtail.
Describe the Ames room illusion
Involves a trapezium shaped room that is longer and higher on one side. However when seen through a peephole the room appears rectangular.
Define visual illusion
A consistent misinterpretation of real sensory information.
Define synaesthesia
A perceptual experience in which a stimulation of one sense produces unusual experiences in another sense.
Taste perception process
The chemical molecules combine with saliva in your mouth to form tastants
The tastants stimulate the taste receptors.
The taste recepters convert the chemical molecules into signals that are transmitted to the brain by facial nerves.
The signals are sent to the thalamus and then to the gustatory cortex to process the taste.
